GitHub Advisoryadvisory · npm
GHSA-55wc-3pg8-jfw6 undici vulnerable to Denial of Service via unhandled exception in the decompress interceptor
MEDIUM
Official page ↗
- Aliases
- CVE-2026-87029
- Ecosystem
- npm
- Packages
- undici
- Severity
- Moderate
- CVSS vector
- CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weaknesses
- CWE-248
- Reviewed
- 2026-10-27
Affected packages
• npm undici: >= 7.15.0, < 7.30.1 → fixed in 7.30.1
• npm undici: >= 8.0.0, < 8.12.2 → fixed in 8.12.2
Description
Impact
undici's `decompress` interceptor forwards decompressed response data to the downstream handler from zlib stream event callbacks without catching exceptions those callbacks may throw. undici's engine converts a synchronous throw from a downstream handler into a per-request failure, but that protection is not in place when the throw happens asynchronously from a zlib callback. As a result, a downstream handler that throws by design, for example the built-in `dump` interceptor which throws when a response exceeds its `maxSize`, escapes as an uncaught exception and terminates the Node.js process.
A malicious or compromised HTTP server can crash any client that composes the `decompress` interceptor with `dump` (or another response handler that throws), by returning a small compressed body that decompresses to more than the configured limit. The compressed bytes on the wire are tiny, so only the decompressed size matters. If the application keeps the process alive with a global uncaught-exception handler, the affected request instead hangs until the body timeout.
Patches
Upgrade to undici 7.30.1 or 8.12.2.
Workarounds
Avoid composing the `decompress` interceptor with a response handler that throws during response processing (such as `dump` with a `maxSize`) until upgrading.
Related
Alias · CVE (1)
- CVE-2026-87029 undici is an HTTP client library for Node.js. vulnerability
Weakness · CWE (1)
- CWE-248 Uncaught Exception weakness
References
- https://github.com/nodejs/undici/security/advisories/GHSA-55wc-3pg8-jfw6 web
- https://nvd.nist.gov/vuln/detail/CVE-2026-87029 advisory
- https://github.com/nodejs/undici/commit/63cba7712ca012b2603c6aeeb4c72d8692332cd0 web
- https://github.com/nodejs/undici/commit/f851f315db1f2acce0ea668f88d9d0fa61c8420c web
- https://cna.openjsf.org/security-advisories.html web
- https://github.com/nodejs/undici package
- https://github.com/nodejs/undici/releases/tag/v7.30.1 web
- https://github.com/nodejs/undici/releases/tag/v8.12.2 web